SANTA LUCIA, Argentina - Cows grazing freely on the vast Pampas have long been part of Argentine tradition. Now that view is changing as ranchers herd their cattle into feedlots.

Breaking with a history of cattle roaming the plains, feeding on grass and herded by gauchos, many farmers are looking to increase efficiency and free up land to grow more profitable grains.

"The feedlot system is here to stay, there is no turning back," said Ignacio Rivarola, president of Proteco S.A., a cattle feedlot operator.

Historically one of the world's leading beef producers and an agricultural powerhouse, Argentina has ridden a boom in soybean prices in recent years to become a top global soy exporter.

Soybean prices have plummeted in recent months, but in their long climb, farmers moved their free-range cattle off Argentina's most fertile lands and into corrals.

Today, mearly 40 percent of Argentina's cattle -- some 12-13 million head -- have been driven into feedlots, nearly three times the number in 2001.

Feedlots, the holding pens where cattle are fattened before slaughter, are widely used in the United States and Europe, but have been slow to catch on among Argentine farmers.

And, unlike in other countries where cattle are essentially raised in feedlots, in Argentina they spend only up to four months in corrals.

In Santa Lucia, some 125 miles northwest of Buenos Aires, Proteco has built a cattle raising complex complete with corrals, troughs, and resting areas for cows -- even streets for them to meander on.

While the changes in cattle-ranging methods have been embraced by producers, some Argentines, including Buenos Aires chefs and grill masters, complain the country's famous beef doesn't quite taste the same.

"Beef from grass-fed cows has a more intense flavor and more texture," said Martiniano Molina, a popular Argentine chef known for his beef recipes.

"You can hardly find that meat now in the cities, so I look for it every time I go to the countryside."

Cacho Paez, who mans the grill at the 1880 steakhouse in Buenos Aires, agreed.

"Beef from feedlot cows is more tender, but it doesn't have as much flavor," he said.

Feedlot cattle producers brush off the complaints.

"Flavor is subjective. Argentines are developing a growing appreciation for beef from feedlots," said Rodrigo Troncoso, the head of a trade group representing feedlot companies.

Feedlot use has grown in part because of government subsidies aimed at stimulating beef production to meet growing demand both at home and abroad.

Argentines are the world's most voracious beef eaters, consuming nearly 154 pounds per person a year. Local beef prices are a hot-button political issue, and the government has curbed beef exports to tamp down prices while at the same time searching for ways to increase supply.

Beef experts insist grain-fattened beef has its advantages, including better production consistency and an intense red color, which frequently catches the eye of consumers willing to pay higher prices.

And feedlot operators say their method has helped keep production stable despite the increased farming of soy and other grains.